[1][2] Quennessen was born near Paris in Boulogne-Billancourt, of Jewish French/Polish parentage, and dedicated much of her childhood to pursuing her dream of becoming an acrobat.

By her teens, she had given up acrobatics and enrolled in acting classes, not because she particularly wanted to get into show business, but to help her overcome social anxiety.

She studied drama first briefly at the École nationale supérieure des arts et techniques du théâtre, then at the Conservatoire National d'Art Dramatique, in Paris, from 1976 to 1979, and appeared in several theater productions, notably Chers Zoiseaux, by Jean Anouilh, which premiered in 1976, and Pirandello's Nuova colonia (1977).

This story of a love triangle on the Greek island of Santorini also starred Peter Gallagher and Daryl Hannah.

In November 2023, the Tampa Bay Times, citing IMDb, reported that, during the filming of the movie, Valérie Quennessen, who played Lina, an archaeologist, discovered pottery at the Akrotiri site that was circa 3,500 years old.